Naing Ngan Linn, a sitting MP for the National League for Democracy, was wounded as his campaign group toured Yangon's Tharketa township, where he is contesting, late yesterday.

"(A man) started punching an NLD member. Then people tried to make him go home because he was drunk. But he came back with a large knife," said Thet Htar Nwe Win, another NLD candidate, who witnessed the incident.

"Naing Ngan Linn tried to stop him... that's why he sustained many injuries," he said, adding three other NLD members suffered minor wounds.

It was not clear what motivated the attack. Thet Htar New Win said at least two people had been arrested.

Political tensions are high in former junta-run Myanmar, where Suu Kyi's opposition is contesting nationwide elections for the first time in a quarter of a century.

The party is likely to make major gains in the vote, potentially tipping the balance of power away from the military and its ruling party allies for the first time in generations.